I have previously set up two servers with multi-master replication, using the cn=config configuration format (I think I've seen it referred to as 'OLC'?). It was a process similar to this (although this is not the guide I followed):
Both my configuration database and actual user database are replicated between both, and I have tested that changes work as expected in both directions.
I need to add a third host into the replication. (Ultimately I am removing one server and replacing it with the third, but there will be a few months of overlap.) I have not been able to find any information on the recommended way to add a new server into a multi-master setup. Is it possible, and if so, what is the recommended way?